Regulation of the BCR signalosome by the class II peptide editor, H2-M, affects the development and repertoire of innate-like B cells.

The non-classical Major Histocompatibility Complex class II (MHCII) protein, H2-M, edits peptides bound to conventional MHCII in favor of stable peptide/MHCII (p/MHCII) complexes. Here, we show that H2-M deficiency affects B-1 cell survival, reduces cell renewal capacity, and alters immunoglobulin repertoire, allowing for the selection of cells specific for highly abundant epitopes, but not low-frequency epitopes. H2-M-deficient B-1 cells have shorter CDR3 length, higher content of positively charged amino acids, shorter junctional regions, less mutation frequency, and a skewed clonal distribution.

Hematopoietic Stem Cell Requirement for Macrophage Regeneration Is Tissue Specific.

Tissue-resident macrophages (TRMΦ) are important immune sentinels responsible for maintaining tissue and immune homeostasis within their specific niche. Recently, the origins of TRMΦ have undergone intense scrutiny, in which now most TRMΦ are thought to originate early during embryonic development independent of hematopoietic stem cells (HSCs). We previously characterized two distinct subsets of mouse peritoneal cavity macrophages (MΦ) (large and small peritoneal MΦ) whose origins and relationship to both fetal and adult long-term (LT) HSCs have not been fully investigated.

Ultra-selective carbon nanotubes for photoacoustic imaging of inflamed atherosclerotic plaques.

Disruption of vulnerable atherosclerotic plaques often leads to myocardial infarction and stroke, the leading causes of morbidity and mortality in the United States. A diagnostic method that detects high-risk atherosclerotic plaques at early stages could prevent these sequelae. The abundance of immune cells in the arterial wall, especially inflammatory Ly-6C monocytes and foamy macrophages, is indicative of plaque‎ inflammation, and may be associated with plaque vulnerability.

IL-6 signaling mediates the germinal center response, IgM production and nociceptive sensitization in male mice after tibia fracture.

Background: Up-regulated interleukin 6 (IL-6) signaling, immune system activation, and pronociceptive autoantibodies are characteristic of complex regional pain syndrome (CRPS). IL-6 is known to promote B cell differentiation, thus we hypothesized that IL-6 signaling plays a crucial role in the development of adaptive immune responses and nociceptive sensitization in a murine tibia fracture model of CRPS.

Methods: Mice deficient in IL-6 expression (IL-6) or B cell deficient (muMT) underwent tibia fracture and 3 weeks of cast immobilization or sham injury.

CTLA-4 expression by B-1a B cells is essential for immune tolerance.

CTLA-4 is an important regulator of T-cell function. Here, we report that expression of this immune-regulator in mouse B-1a cells has a critical function in maintaining self-tolerance by regulating these early-developing B cells that express a repertoire enriched for auto-reactivity. Selective deletion of CTLA-4 from B cells results in mice that spontaneously develop autoantibodies, T follicular helper (Tfh) cells and germinal centers (GCs) in the spleen, and autoimmune pathology later in life.

Germinal center formation, immunoglobulin production and hindlimb nociceptive sensitization after tibia fracture.

Emerging evidence suggests that Complex Regional Pain Syndrome (CRPS) is in part a post-traumatic autoimmune disease mediated by an adaptive immune response after limb injuries. We previously observed in a murine tibial fracture model of CRPS that pain-related behaviors were dependent upon adaptive immune mechanisms including the neuropeptide-dependent production of IgM for 5 months after injury. However, the time course of induction of this immune response and the demonstration of germinal center formation in lymphoid organs has not been evaluated.

Hematopoietic stem cell-independent hematopoiesis and the origins of innate-like B lymphocytes.

The current paradigm that a single long-term hematopoietic stem cell can regenerate all components of the mammalian immune system has been challenged by recent findings in mice. These findings show that adult tissue-resident macrophages and innate-like lymphocytes develop early in fetal hematopoiesis from progenitors that emerge prior to, and apparently independently of, conventional long-term hematopoietic stem cells. Here, we discuss these recent findings, which show that an early and distinct wave of hematopoiesis occurs for all major hematopoietic lineages.

Automated subset identification and characterization pipeline for multidimensional flow and mass cytometry data clustering and visualization.

When examining datasets of any dimensionality, researchers frequently aim to identify individual subsets (clusters) of objects within the dataset. The ubiquity of multidimensional data has motivated the replacement of user-guided clustering with fully automated clustering. The fully automated methods are designed to make clustering more accurate, standardized and faster.

QFMatch: multidimensional flow and mass cytometry samples alignment.

Part of the flow/mass cytometry data analysis process is aligning (matching) cell subsets between relevant samples. Current methods address this cluster-matching problem in ways that are either computationally expensive, affected by the curse of dimensionality, or fail when population patterns significantly vary between samples. Here, we introduce a quadratic form (QF)-based cluster matching algorithm (QFMatch) that is computationally efficient and accommodates cases where population locations differ significantly (or even disappear or appear) from sample to sample.

Evidence for altered levels of IgD in the nasal airway mucosa of patients with chronic rhinosinusitis.

Background: IgD is an enigmatic antibody isotype best known when coexpressed with IgM on naive B cells. However, increased soluble IgD (sIgD) levels and increased IgDIgM B-cell populations have been described in the human upper respiratory mucosa.

Objective: We assessed whether levels of sIgD and IgD B cell counts are altered in nasal tissue from patients with chronic rhinosinusitis (CRS).

Earth Mover's Distance (EMD): A True Metric for Comparing Biomarker Expression Levels in Cell Populations.

Changes in the frequencies of cell subsets that (co)express characteristic biomarkers, or levels of the biomarkers on the subsets, are widely used as indices of drug response, disease prognosis, stem cell reconstitution, etc. However, although the currently available computational "gating" tools accurately reveal subset frequencies and marker expression levels, they fail to enable statistically reliable judgements as to whether these frequencies and expression levels differ significantly between/among subject groups. Here we introduce flow cytometry data analysis pipeline which includes the Earth Mover's Distance (EMD) metric as solution to this problem.

Characterization of immunoglobulin E plasma cells that are elevated in the upper airway mucosa of nonatopic patients with chronic rhinosinusitis without nasal polyps.

Background: The immunologic mechanisms driving inflammation in the upper airways of patients with chronic rhinosinusitis (CRS) are poorly understood. Previous studies have shown that B cells and immunoglobulin E (IgE) levels are elevated in the nasal tissue of patients with atopic chronic rhinosinusitis without nasal polyps (CRSsNP). However, less is known regarding B cell subsets and IgE-producing plasmablasts in nonatopic CRSsNP patients.

Fetal Hematopoietic Stem Cell Transplantation Fails to Fully Regenerate the B-Lymphocyte Compartment.

B cells are key components of cellular and humoral immunity and, like all lymphocytes, are thought to originate and renew from hematopoietic stem cells (HSCs). However, our recent single-HSC transfer studies demonstrate that adult bone marrow HSCs do not regenerate B-1a, a subset of tissue B cells required for protection against pneumonia, influenza, and other infections. Since B-1a are regenerated by transfers of fetal liver, the question arises as to whether B-1a derive from fetal, but not adult, HSCs.

Amyloid fibrils activate B-1a lymphocytes to ameliorate inflammatory brain disease.

Amyloid fibrils composed of peptides as short as six amino acids are therapeutic in experimental autoimmune encephalomyelitis (EAE), reducing paralysis and inflammation, while inducing several pathways of immune suppression. Intraperitoneal injection of fibrils selectively activates B-1a lymphocytes and two populations of resident macrophages (MΦs), increasing IL-10 production, and triggering their exodus from the peritoneum. The importance of IL-10-producing B-1a cells in this effective therapy was established in loss-of-function experiments where neither B-cell-deficient (μMT) nor IL10(-/-) mice with EAE responded to the fibrils.

Blood basophil activation is a reliable biomarker of allergic bronchopulmonary aspergillosis in cystic fibrosis.

The diagnosis of cystic fibrosis (CF) patients with allergic bronchopulmonary aspergillosis (ABPA) is clinically challenging, due to the absence of an objective biological test. Since blood basophils play a major role in allergic responses, we hypothesised that changes in their surface activation pattern discriminate between CF patients with and without ABPA.We conducted a prospective longitudinal study (Stanford cohort) comparing basophil activation test CD203c levels by flow cytometry before and after activation with Aspergillus fumigatus allergen extract or recombinant Asp f1 in 20 CF patients with ABPA (CF-ABPA) and in two comparison groups: CF patients with A.

Distinct mechanisms define murine B cell lineage immunoglobulin heavy chain (IgH) repertoires.

Processes that define immunoglobulin repertoires are commonly presumed to be the same for all murine B cells. However, studies here that couple high-dimensional FACS sorting with large-scale quantitative IgH deep-sequencing demonstrate that B-1a IgH repertoire differs dramatically from the follicular and marginal zone B cells repertoires and is defined by distinct mechanisms. We track B-1a cells from their early appearance in neonatal spleen to their long-term residence in adult peritoneum and spleen.

Co-administration of N-Acetylcysteine and Acetaminophen Efficiently Blocks Acetaminophen Toxicity.

Preclinical Research Although acetaminophen (APAP) is an effective analgesic and anti-pyretic, APAP overdose is the most frequent cause of serious, often lethal, drug-induced hepatotoxicity. Administration of N-acetyl cysteine (NAC) within 8 hours of APAP overdose effectively mitigates APAP-induced hepatotoxicity. Thus, preventing APAP toxicity before it occurs by formulating APAP with NAC is logical and, as we show here in a mouse model, is effective in preventing APAP toxicity.

Layered evolution in the immune system: a view from history.

Although much had still to be learned, evidence indicating that B-1a lymphocytes very likely belonged to a distinct lineage was largely in place by the time of the first large B-1a conference in 1991. The widely respected group of immunologists attending that meeting (including Tasuko Honjo and Klaus Rajewsky) developed and ultimately published the B-1a notation still in use today. Here, I briefly review some of the early B-1a findings that underlie current studies.

Cysteine Oxidation Targets Peroxiredoxins 1 and 2 for Exosomal Release through a Novel Mechanism of Redox-Dependent Secretion.

Nonclassical protein secretion is of major importance as a number of cytokines and inflammatory mediators are secreted via this route. Current evidence indicates that there are several mechanistically distinct methods of nonclassical secretion. We have shown recently that peroxiredoxin (Prdx) 1 and Prdx2 are released by various cells upon exposure to inflammatory stimuli such as lipopolysaccharide (LPS) or tumor necrosis factor alpha (TNF-α).

Long-term treatment with oral N-acetylcysteine: affects lung function but not sputum inflammation in cystic fibrosis subjects. A phase II randomized placebo-controlled trial.

Purpose: To evaluate the effects of oral N-acetylcysteine (NAC), which replenishes systemic glutathione, on decreasing inflammation and improving lung function in CF airways.

Methods: A multicenter, randomized, double-blind proof of concept study in which 70 CF subjects received NAC or placebo orally thrice daily for 24 weeks.

Endpoints: primary, change in sputum human neutrophil elastase (HNE) activity; secondary, FEV(1) and other clinical lung function measures; and safety, the safety and tolerability of NAC and the potential of NAC to promote pulmonary hypertension in subjects with CF.